This invention relates generally to roof bows and more particularly to a composite roof bow used with an automotive vehicle convertible roof.
It is well known to employ a plurality of roof bows for suspending a soft top convertible roof above a passenger compartment of an automotive vehicle. The roof bows are secured to the top by way of staple-like fasteners or placement of each bow within a pocket sewn to the lower side of the convertible roof. The soft top roof is commonly secured to the number one or forwardmost roof bow by being sandwiched between the number one bow and a trim panel. The roof bows are usually metal and extend in a cross-car manner between metal side rails which are oriented in a generally fore and aft manner. For example, a roof bow and side rail top stack mechanism are disclosed in U.S. Pat. No. 4,720,133 entitled "Convertible Top Structure" which issued to Alexander et al. on Jan. 19, 1988, the disclosure of which is incorporated by reference herein. Such traditional convertible roofs are movable from a raised and operable position covering the passenger compartment, to a stowed and retracted position in a bootwell between the passenger compartment and vehicle trunk.
Some conventional roof bow constructions have also attempted to combine metal with other assembled materials. For example, reference should be made to the following U.S. Pat. No.: 5,560,670 entitled "Top Bow Tack Strip" which issued to Boardman on Oct. 1, 1996; U.S. Pat. No. 2,580,337 entitled "Folding Top Structure" which issued to Votypka on Dec. 25, 1951; U.S. Pat. No. 2,538,931 entitled "Bow and Tacking Strip Assembly" which issued to Zummach on Jan. 23, 1951; U.S. Pat. No. 1,789,137 entitled "Reinforced [sic] Wooden Bow and method of Manufacture Thereof" which issued to Fitch on Jan. 13, 1931; and U.S. Pat. No. 366,511 entitled "Carriage Bow" which issued to Sampsell on Jul. 12, 1887. The wood roof bows are heavy, expensive to shape and are not dimensionally stable in wet weather. Moreover, for the versions employing unfilled plastic, the plastic bows appear to be relatively flexible and offer little freestanding structural support over the great distances spanned, especially when it is considered that the vehicle is often moving at high speeds on rough roads.
U.S. Pat. No. 5,427,429 entitled "Convertible Top Bow" which issued to Piontek et al. on Jun. 27, 1995, discloses a glass reinforced polymeric roof bow. Metal linkage hardware can be molded in place at the ends of the polymeric bow. While this patent is a significant improvement in the industry, it is desirable to further improve the characteristics of a rigid plastic roof bow by providing an additional metal insert in an area of the bow between the roof rail engaging ends.
In accordance with the present invention, a preferred embodiment of a composite roof bow includes a flexible plastic segment and a rigid reinforcing segment. In another aspect of the present invention, the flexible plastic segment is insert molded to the reinforcing segment. In another aspect of the present invention, the flexible segment is predominately unfilled plastic and the reinforcing segment is filled plastic, which are attached together to create a generally rigid roof bow. Still a further aspect of the present invention provides a metal reinforcing segment entirely disposed inside the plastic segment and the plastic segment has a generally I-cross sectional shape. In yet another aspect of the present invention, a reinforcement extends at least a majority of the cross-car length of the plastic bow. A method of making an automotive vehicle roof bow is also provided.
The composite roof bow of the present invention is advantageous over traditional bows in that the present invention advantageously uses the relatively lightweight and rigid property of a filled plastic while also minimizing brittle fracture of the plastic by employing either an unfilled plastic or a metallic reinforcement. The present invention is also advantageous by employing a low piece cost and fast method of manufacturing the composite bow with a minimal amount of manual assembly. The present invention achieves predictable tolerances regardless of environmental humidity while also employing relatively few parts to assemble the bow to a soft top convertible roof. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.